Energy-Based Approach to Evaluation of Short Fatigue Crack Growth Rate in Plates

Generalization of the equivalent area method for the case of short fatigue cracks in a three-dimensional body

“…The growth rate of the circular crack based on ( 7) can be written in the following form as a function of the opening of its fracture process zone [8]:…”

“…Then having substituted (22) into the obtained formula for determination of the opening of the fracture process zone in front of a crack contour (18) and having grouped the dimensionless loading values p * /σ t and crack sizes a/a * , we obtain the following expression for the critical loading: In addition, let us conduct a numerical experiment based on the generalized Sack's problem for the steel 65Ã (analogue to 1066) using the proposed formula for determination of the opening of the fracture process zone (19). On Grith's problem, it has been veried [8,11,12] that the approach to present the crack growth rate via the opening in its tip is invariant contrary to the employment of a stress intensity factor. Let us use this approach to Sack's problem for a three-dimensional body.…”

“…Then, the combination of ( 6), ( 4) and (3) gives the following formula for the fatigue crack growth rate [8]:…”